Metal Plating Using Seed Film

ABSTRACT

A seed film and methods incorporating the seed film in semiconductor applications is provided. The seed film includes one or more noble metal layers, where each layer of the one or more noble metal layers is no greater than a monolayer. The seed film also includes either one or more conductive metal oxide layers or one or more silicon oxide layers, where either layer is no greater than a monolayer. The seed film can be used in plating, including electroplating, conductive layers, over at least a portion of the seed film. Conductive layers formed with the seed film can be used in fabricating an integrated circuit, including fabricating capacitor structures in the integrated circuit.

TECHNICAL FIELD

The invention relates to fabrication of integrated circuits and, moreparticularly, to plating of metal layers using seed films in integratedcircuit fabrication.

BACKGROUND

Formation of conductive materials is an important fabrication process inintegrated circuit (IC) production. Thin conductive films are used increating any number of IC structures. Examples of these structuresinclude, for example, interconnects, capacitor electrodes (e.g.,metal-insulator-metal (MIM) electrodes), etc.

The requirements of a conductive material formation process can bedemanding. In many cases, for example, conductive films need to bedeposited at reasonably low temperatures tolerated by other materialsused in integrated circuits. In addition, for example, the conductivefilms need to be high quality conformal films formed over a substratesurface, e.g., openings, deep trenches, container capacitor openings,etc. Furthermore, such films need to be formed with high throughput.

Various processes can be used to form such films. For example, physicalprocesses (e.g., physical vapor deposition (PVD), evaporation,sputtering) or chemical processes (e.g., chemical vapor deposition (CVD)or plating) may be used. In addition, electroplating has beenadvantageously used in forming conductive and conformal films at highthroughput.

In the electroplating process, a seed film can be initially applied toIC structures during processing. The seed film can then be used as aconductive surface on which the electroplating process can then takeplace. The seed films are typically formed by either the physical orchemical film forming process mentioned above. Typical processes forforming seed films used in electroplating conductive films, however,have various disadvantages. For example, seed films produced by eitherCVD or PVD in many circumstances require an overabundance of seed filmto be deposited to ensure film continuity. The result of thisoverabundance is that certain areas of the seed film have thickerdeposits as compared to other areas. This is especially true for highaspect ratio structures, such as openings or trenches (e.g., containercapacitor openings), which typically require a thick deposit in order toyield sufficient seed layer on the side of the walls of the structurefor successful plating therein. Further, for example, adhesion of anelectroplated layer to seed films deposited by PVD may only be marginal.

In a specific example, electroplated platinum is an attractive candidatefor a bottom MIM electrode because of the high quality conformal filmsthat can be deposited at high throughput. The typical PVD platinum seedlayer, however, could be improved since it requires a thick deposit inorder to yield sufficient platinum on the sidewalls of the container forsuccessful plating. Also, adhesion is only marginal with the PVDplatinum seed layer.

Thus, a need exists for creating uniform seed films for use in theelectroplating process.

SUMMARY OF THE INVENTION

In view of the foregoing, there is a need in the semiconductor art forcreating uniform seed films for use in electroplating processes.Accordingly, the present invention is directed to an electroplatingmethod for use in fabricating an integrated circuit, a method forplating, a method for use in fabricating a capacitor, a seed film foruse in electroplating a conductive layer, and a capacitor for anintegrated circuit.

One aspect of the present invention provides a plating method, includingan electroplating method, where the plating method can be used infabricating an integrated circuit. Preferably, the method includesforming a seed film on at least a portion of a surface of a substrateassembly by atomic layer deposition, where the seed film comprises atleast a noble metal and a conductive metal oxide, and plating aconductive layer over at least a portion of the seed film.

The method may also include repeating one or more deposition cycles informing the seed film, where at least one of the one or more depositioncycles includes providing a predetermined amount of one or more noblemetal containing precursors, and providing a reactant for use inconverting at least one of the one or more noble metal precursors toless than a monolayer of at least one noble metal of the one or morenoble metal containing precursors. The method may also include oxidizingat least a portion of the monolayer of the at least one noble metal.

Preferably, the conductive metal oxide is at least one noble metal oxideselected from a group consisting of iridium oxide, ruthenium oxide, andrhodium oxide. In addition, the at least one noble metal of the presentinvention comprises at least one noble metal selected from a groupconsisting of iridium, ruthenium, platinum, and rhodium.

According to one aspect of the present invention, plating a conductivelayer comprises forming at least a portion of an electrode of acapacitor structure using the seed film. Preferably, plating theconductive layer over the seed film includes chemical vapor depositingconductive material over at least a portion of the seed film, andplating the conductive layer over the conductive material and the seedfilm. In one embodiment, plating the conductive layer compriseselectroplating a conductive layer comprising platinum over at least aportion of the seed film.

The present invention also includes an additional plating method,including an electroplating method for use in fabricating an integratedcircuit. Preferably, the plating method includes forming a seed film onat least a portion of a surface of a substrate assembly by atomic layerdeposition, where the seed film comprises at least a noble metal, asdiscussed, and an oxide material, and plating a conductive layer over atleast a portion of the seed film.

The method may also include repeating one or more deposition cycles informing the seed film, where at least one of the one or more depositioncycles includes providing a predetermined amount of one or more noblemetal containing precursors, and providing a reactant for use inconverting at least one of the one or more noble metal precursors toless than a monolayer of at least one noble metal of the one or morenoble metal containing precursors. In addition, forming the seed filmcan include repeating one or more deposition cycles, where at least oneof the one or more deposition cycles includes providing a Si containingprecursor, and providing a reactant for use in converting at least aportion of the Si containing precursor to less than a monolayer ofsilicon oxide.

According to one aspect of the present invention, plating a conductivelayer includes forming at least a portion of an electrode of a capacitorstructure using the seed film. Preferably, plating the conductive layerover the seed film includes chemical vapor depositing conductivematerial over at least a portion of the seed film, and electroplatingthe conductive layer over the conductive material and the seed film. Inone embodiment, plating the conductive layer comprises electroplating aconductive layer comprising platinum over at least a portion of the seedfilm.

An additional aspect of the present invention includes a method for usein fabricating a capacitor, including a capacitor for an integratedcircuit. Preferably, the capacitor includes a substrate assembly, abottom electrode over at least a portion of the substrate assembly, adielectric layer on the bottom electrode, and a top electrode on thedielectric layer. Preferably, at least one of the bottom electrode andthe top electrode comprise an ALD deposited seed film comprising one ormore noble metal layers, as described, and one or more conductive metaloxide layers, as described, where each of the one or more noble metallayers and one or more conductive metal oxide layers is no greater thana monolayer, and further where the at least one of the bottom electrodeand the top electrode comprises at least one conductive layer formed onthe seed layer.

In an alternative embodiment, the at least one of the bottom electrodeand the top electrode comprise an ALD deposited seed film positionedbetween integrated circuit substrate assembly and the top electrode,where the conformal seed film comprises one or more noble metal layers,as described, and one or more oxide material layers, as described, whereeach of the one or more noble metal layers and one or more oxidematerial layers is no greater than a monolayer, and further where the atleast one of the bottom electrode and the top electrode comprises atleast one conductive layer formed as the seed layer.

In one preferred embodiment, the conformal seed film is between asurface of the substrate assembly and the bottom electrode. In analternative preferred embodiment, the capacitor further includes asecond conformal seed film, where the second conformal seed film isbetween the dielectric layer and the top electrode.

Fabricating the capacitor includes forming a bottom electrode, forming adielectric layer on the bottom electrode, and forming a top electrode onthe dielectric layer. In one example, forming at least one of the bottomelectrode and top electrode includes forming a seed film comprising oneor more noble metal layers and one or more conductive metal oxide layersby atomic layer deposition, where each of the one or more noble metallayers and conductive metal oxide layers is not greater than amonolayer, and plating at least one electrode material on at least aportion of the seed film. Preferably, the bottom electrode can be formedusing the seed film.

In an additional example, forming at least one of the bottom electrodeand top electrode includes forming a seed film comprising one or morenoble metal layers and one or more oxide material layers by atomic layerdeposition, where each of the one or more noble metal layers and oxidematerial layers is not greater than a monolayer, and plating at leastone electrode material on at least a portion of the seed film.Preferably, the bottom electrode can be formed using the seed film.

An additional aspect of the present invention provides a seed film foruse in electroplating a conductive layer. The seed film can include oneor more noble metal layers, as described, where each layer of the one ormore noble metal layers is no greater than a monolayer. In oneembodiment, the seed film also includes one or more conductive metaloxide layers, as described, where each layer of the one or moreconductive metal oxide layers is no greater than a monolayer. In analternatively embodiment, the seed film includes one or more siliconoxide layers, as described, where each layer of the one or more siliconoxide layers is no greater than a monolayer.

According to one aspect of the present invention, the seed film includesalternating layers of the one or more noble metal layers and the one ormore conductive metal oxide layers. Alternatively, the seed filmincludes alternating layers of the one or more noble metal layers andthe one or more silicon oxide layers. In one preferred embodiment, theone or more noble metal layers comprise platinum and the one or moreconductive metal oxide layers comprise rhodium oxide. In an additionalpreferred embodiment, the first series of noble metal layers areplatinum, and the second series of silicon oxide layers are silicondioxide.

Preferably, the seed film for use in electroplating a conductive layerof the present invention includes one or more platinum layers, whereeach layer of the one or more platinum layers is no greater than amonolayer, and one or more rhodium oxide layers, where each layer of theone or more of rhodium oxide layers is no greater than a monolayer. Inan additional preferred aspect of the present invention, the seed filmfurther includes alternating layers of the one or more platinum layersand the one or more rhodium oxide layers.

In an additional preferred embodiment, the seed film for use inelectroplating a conductive layer includes one or more platinum layers,where each layer of the one or more platinum layers is no greater than amonolayer, and one or more silicon dioxide layers, where each layer ofthe one or more silicon dioxide layers is no greater than a monolayer.Preferably, the seed film can further include alternating layers of theone or more platinum layers and the one or more silicon dioxide layers.

These and other features and advantages of the present invention will beapparent from the following description of various embodiments and asillustrated in the accompanying figures.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of a substrateassembly having a seed film formed thereon according to the presentinvention.

FIG. 2 is a cross-sectional view of another embodiment of a substrateassembly having a seed film and an optional conductive film formedthereon according to the present invention.

FIG. 3 is a cross-sectional view of a generalized electroplatingapparatus according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conductive layer plated on theseed layer formed on a substrate assembly as shown in FIG. 2.

FIG. 5 is a cross-sectional view of a capacitor structure incorporatingan electrode formed by electroplating using a seed film according to thepresent invention.

DETAILED DESCRIPTION

Generally, the present invention provides seed films for electroplatingprocesses and methods of using the seed films in electroplatingconductive material, e.g., platinum, on a substrate assembly. Inaddition, the present invention provides for electrode and capacitorstructures formed on substrate assemblies through the use of the seedfilms and electroplating methods of the present invention. Other methodsand structures are also presented.

The present invention can be especially useful in providing seed filmson surfaces of substrate assemblies that have high aspect ratios. Highaspect ratio structures include those having an aspect ratio of greaterthan about 1:1. This includes structures that have aspect ratios thatare 10:1 or even larger. In addition, the high aspect ratio structuresmay generally include critical dimensions that are less than 1 micron.In addition to high aspect ratio structures, the present invention canbe useful in providing uniform seed films over any number of ICsubstrate structures that have traditionally been difficult to providewith a uniform seed film. Examples of such structures include, but arenot limited to, trenches, container capacitor openings, interconnectopenings such as a damascene structure, contacts, and vias.

The present invention provides seed films and methods of forming seedfilms for use in plating conductive layers. For example, the seed filmsof the present invention can be used in electroplating of platinumand/or platinum alloy layers. Specifically, the present invention isdirected to the use of atomic layer deposition (ALD) in forming seedfilms on at least a portion of a surface of a substrate assembly. ALDcan be used to form seed films that conform to substrate surfaces, eventhose surfaces that define high aspect ratios. The seed films formed byALD according to the present invention can then be used inelectroplating a conductive material on the seed film.

As used in this application, “substrate assembly” refers to either asemiconductor substrate such as the base semiconductor layer, e.g., thelowest layer of silicon material in a wafer, or a silicon layerdeposited on another material such as silicon on sapphire, or asemiconductor substrate having one or more layers or structures formedthereon or regions formed therein. When reference is made to a substrateassembly in the following description, various process steps may havebeen previously used to form or define regions, junctions, variousstructures or features, and openings such as vias, contact openings,high aspect ratio openings, etc.

FIG. 1 provides a general example of a seed film 10 on a substrateassembly 14 for use in electroplating a conductive layer 16 thereonaccording to the present invention. The seed film 10 preferably includesmultiple layers (e.g., one or more atomic or molecular layers) of metaland metal containing material in any number of layering configurations.For example, the seed film 10 preferably includes a seed film formed byALD. Preferably, the seed film 10 formed by ALD may be any film builtprogressively by adding atomic or molecular layers one after anotheruntil a desired thickness is achieved. An atomic or molecular layer maybe any layer less than a monolayer.

In one particular illustrative example, an alternating series of layerscan form the seed film 10. The alternating series of layers may includetwo or more series of layers. For example, the alternating series oflayers may include a first series of layers 18 formed by ALD (e.g.,rhodium oxide layers) and a second series of layers 22 formed by ALD(e.g., platinum layers). In an additional example, forming the firstseries of layers 18 and the second series of layers 22 can beprogressively repeated (e.g., forming the first series of layers 18,followed by the second series of layers 22, followed by the first seriesof layers, followed by the second series 22 of layers, etc.) until adesired thickness of the seed film 10 is achieved.

The series of layers 18 and 22 can each have any number of ALD formedatomic layers (e.g., one or more layers). The exact number of layers foreach series may be dependent upon the type of metal and/or compoundsthat are being deposited. In addition, the exact number of layers foreach series may depend on the desired thickness for the seed film. Ingeneral, the seed film may be formed by, for example, any number oflayers, series of layers, alternating series of layers, as long as theseed film is formed at least in part by progressively adding atomic ormolecular layers one after the other until a desired thickness isachieved.

In one example, the seed film 10 preferably includes one or more layersformed of one or more noble metals (e.g., the first series of layers 18)and one or more layers formed of conductive metal oxides (e.g., thesecond series of layers 22). For example, the one or more layers may beformed of a noble metal or alloys of noble metals. As used herein, noblemetals include, but are not limited to, platinum, ruthenium, rhodium,and iridium. Other noble metals may also include palladium, and osmium.The one or more layers of conductive metal oxide may be formed of noblemetal oxide. Examples of the conductive metal oxide layers include, butare not limited to, ruthenium oxide, rhodium oxide, osmium oxide, andiridium oxide.

In an additional illustrative example, the seed film 10 preferably is anoble metal doped oxide that includes one or more layers formed of oneor more noble metals (e.g., the first series of layers 18) and one ormore layers formed of an oxide material (e.g., the second series oflayers 22). For example, the one or more layers may be formed of a noblemetal or alloys of noble metals. Examples of noble metals are aspreviously discussed. The one or more layers of the oxide material maybe formed of any number of dielectric materials and or non-conductiveoxide materials as long as the film is still conductive. Examples of theoxide material include, but are not limited to, silicon oxide (SiO_(x)),silicon dioxide (SiO₂), Si₃N₄, and Al₂O₃. One example of a seed film 10that includes an oxide doped noble metal is a silicon oxide dopedplatinum seed film 10.

The seed film 10 can be formed by ALD. Layers, less than a monolayer,are deposited during cycles of ALD to form the seed film 10 of thepresent invention. For example, each cycle of ALD may form at least onelayer of a series of the layers 18 and 22. Preferably, in each of theone or more ALD cycles, as is generally known, a predetermined amount ofone or more precursors is provided on the surface upon which the layeris to be formed. The precursor is then converted, (e.g., by oxygen orother reactant) to the desired atomic layer after purging the processchamber. As ALD is a self-limiting process with use of a predepositedamount of precursor prior to conversion, each layer is typicallycontrolled to be no greater than a monolayer. The purging of the chambertypically completes a cycle and future cycles are used for progressivelybuilding material on the previously deposited layer so as to form a veryconformal film.

Examples of noble metal containing precursors used to form noble metallayers or the conductive metal oxide layers may include one or morenoble metal containing precursors (e.g., organometalic precursors) suchas iridium, ruthenium, platinum, and rhodium containing precursors.Specific examples of these precursors include, but are not limited to,MeCpPt(Me)₃, CpRh(CO)₂, CpRu(CO)₃, and CpIr(CO)₂, where Cp iscyclopentadienyl. Preferably, the noble metal containing precursor is aplatinum containing precursor such as MeCpPt(Me)₃, CpPt(Me)₃,Pt(acetylacetonate)₂, Pt(PF₃)₄, Pt(CO)₂Cl₂, cis-[PtMe₂(MeNC)₂], orplatinum hexafluoroacetylacetonate.

Reactants used for converting at least one of the one or more noblemetal containing precursors may include any number of suitablereactants. For example, the reactants can include, but are not limitedto, oxygen such as for forming platinum or rhodium layers; ozone, suchas for forming platinum and also possibly reacting with previouslyformed rhodium to form rhodium oxide; N₂O, or SO₃.

In addition to converting the noble metal precursors, any number ofsuitable reactants may also be used in an oxidative process to produceconductive metal oxides. For example, the reactants can include ozonethat can both provide for the effective formation of a platinum layerfrom a platinum containing precursor and cause the oxidation of apreviously formed layer of rhodium to form rhodium oxide. Other suitablereactants may include O₂, N₂O, and SO₃. Use of one or more of thesereactants can be used in forming other conductive metal oxide layersfrom previously formed metal layers. For example, O₂ can be used informing iridium oxide from a previously formed layer of iridium.

Examples of oxide material (e.g., non-conductive oxide material)precursors used to form oxide material layers may include one or moresilicon containing precursors such as disilane (Si₂H₆), SiH₄, orSiR_(x)H_(y), where R can be either an organic group or a halide.

As discussed, the seed film 10 can include any number of multiple layersof metal and metal compounds (e.g., conductive metal oxides) in anynumber of layering configurations. In a preferred embodiment, the seedfilm 10 includes alternating series of noble metal and conductive metaloxide layers. In a preferred embodiment, the seed film 10 includes oneor more noble metal layers of platinum and one or more conductive metaloxide layers of rhodium oxide.

In an additionally preferred embodiment, the seed film 10 includesalternating series of noble metal and oxide material layers. In apreferred embodiment, the seed film 10 includes one or more noble metallayers of platinum and one or more oxide material layers of siliconoxide (SiO_(x)).

In the above examples, the seed film 10 includes an oxide compound. Forexample, the seed film 10 can include iridium oxide, ruthenium oxide,rhodium oxide, and/or SiO_(x). Seed films of the present invention thatinclude at least one of the oxide compounds have been found to displaysuperior adhesion characteristics with respect to the seed filmsadhesion to the underlying substrate and to the conductive layerelectroplated onto the seed film.

It will be appreciated that the number and order of the seed film layersis dependent, at least, upon the type of metal and/or compounds that arebeing deposited. In addition, the thickness of the seed film 10 can varydepending on the number and thickness of the ALD deposited layers.Preferably, the seed film 10 has a thickness of no less than 20angstroms. In addition, the seed film 10 preferably has a thickness ofno greater than about 500 angstroms. In addition, preferably, the seedfilm 10 has a thickness of no less than 20 angstroms and no greater thanabout 500 angstroms.

As discussed, the seed film 10 is a conductive layer that is used in aplating process according to the present invention. For example, theplating process can include electroplating a conductive material on atleast a portion of the substrate assembly 14. During electroplating, theseed film 10 is used as at least a portion of an electrode (e.g.,cathode) in the conductive material plating process. The result of theelectroplating process is a conductive layer that includes both the seedfilm 10 and the conductive layer 16 deposited by electroplating.

FIG. 2 shows an illustrative embodiment of a seed film 40 of the presentinvention on an IC substrate assembly 44. The IC substrate assembly 44defines an opening 50 having a high aspect ratio. In one example, thehigh aspect ratio is at least a 1:1 aspect ratio and has criticaldimensions of less than 1 micron.

The opening 50 includes a bottom 54 and sidewalls 56 extendingtherefrom. The seed film 40 shows a first series of layers 60 and asecond series of layers 66 deposited by ALD. As previously mentioned,any number of cycles of an ALD process may be used to deposit layers toform the seed film 40. In addition, any technique that progressivelybuilds layers of less than a monolayer can be used in forming the seedfilm. Preferably, the techniques of ALD and/or atomic layer epitaxy canbe used to progressively build layers of less than a monolayer so as toform the seed film.

The seed film 40 is shown as being conformal over the bottom 54 andsidewalls 56 of the substrate assembly 44. The seed film 40 can includeany seed film formed as described in the present application. The ALDprocess provides a conformal seed film 40 that allows for an essentiallyuniform thickness thereof along the contours of the substrate assembly44, particularly in the high aspect ratio opening 50.

In addition to being conformal, the seed film 40 deposited by ALD isalso more continuous than those produced by either CVD or PVD processes.The more conformal and continuous characteristics of the seed film 40resulting from the ALD process provide an advantage over films depositedby either CVD or PVD. These advantages include, but are not limited to,electroplated films being formed that have a more uniform thicknessresulting from a more uniform current density provided over the entireALD seed film during the electroplating process as compared to theresults from the CVD or PVD seed layers.

As discussed above, the seed film 40 preferably has a thickness of noless than 20 Angstroms and no greater than about 500 Angstroms. Thisrange of seed film thickness may be, in certain cases, unable to supportsufficient conductivity across a wafer being processed for an effectiveelectroplating process. As such, the present invention may optionallyprovide a conductive film 70 on the upper surface 76 of the seed layer40. This conductive film 70 is of sufficient thickness to provide aneffective cathode in the electroplating process.

In one example, the conductive film 70 can be formed on at least aportion of the seed film 40 by a chemical vapor deposition (CVD)process, although other processes may be used. The conductive film 70 ispreferably formed on at least the upper surface 76 of the substrateassembly 44 by CVD, but not necessarily on the sidewalls 56 or thebottom 54 of the structure 50. Preferentially, applying the conductivefilm 70 to the upper surface 76 by CVD can be accomplished by adjustingreaction pressures of the CVD process in such a way that coverage iseffected on the upper surface 76, but not necessarily in the opening 50(e.g., essentially none of the material deposited by CVD enters theopening 50, but only deposits on the upper surface 76 of the seed layer40 on substrate assembly 44).

The conductive film 70 can be formed from any number of conductivematerials that can be deposited by the CVD process. For example, theconductive film 70 can be formed from a noble metal such as platinum.Forming the conductive film 70 from other noble metals is also possible.

In one embodiment, the CVD process can be used to form a conductive film70 of at least 100 Angstroms over the upper surface 76 of the seed film40. Alternatively, the CVD process can be used to form the conductivefilm 70 of no greater than 300 Angstroms over the upper surface 76 ofthe seed film 40.

The conductive film 70 and the seed film 40 can then be used in anelectroplating process. Electroplating using the conductive film 70 andthe seed film 40 can be accomplished through any variety ofelectroplating techniques. For example, an electroplating process isdescribed in U.S. Pat. No. 6,344,126 to Moore, which is incorporatedherein by reference in its entirety.

FIG. 3 illustrates one general example of an electroplating apparatus 80for use in electroplating over the conductive film 70 and the seed film40. The apparatus 80 includes a tank 84 containing electroplatingsolution 88, a support 92 for supporting substrate assembly 44 in thesolution 88, and a target (anode) 94 containing conductive material(e.g., platinum, platinum alloy, etc.). The wafer support 92 may havemetal clips 100 and 104 for holding the substrate assembly 44 in thedesired position. The seed film 40 and the conductive film 70 can beelectrically connected through the clips 100 and 104 and suitable wireelements 116.

In operation, a voltage is applied to the target 94 by a control device120. The electrical potential between the cathode (e.g., seed layer40/conductive layer 70) and the anode (e.g., the target 94 containingconductive material) causes current to flow from the target 94, throughthe solution 88, through the conductive film 70 and the seed film 40,and through the clips 100 and 104 to the wire elements 116. Theelectroplating process causes a migration of conductive material fromthe target 94 to the cathode for formation of an electroplatedconductive layer 130 (FIG. 4) on the conductive film 70 and the seedfilm 40. The process may be continued until the electroplated conductivelayer 130 achieves the desired thickness. The electroplated substrateassembly 44 may then be removed from the tank 84 for further processing.

With respect to the electroplating process of the present invention, anynumber of conductive materials can be used in forming structures on thesubstrate assembly. In addition, any number of layers (e.g., one ormore) can be formed with the electroplating process in one or moreprocesses in one or more electroplating chambers. Examples of conductivematerials for plating on the substrate assembly include, but are notlimited to, noble metals, alloys of noble metals, or combinationsthereof. Preferably, the noble metal is platinum or an alloy thereof.Additional metals can also be used as plating materials. These metalsinclude, but are not limited to, nickel and/or nickel compounds, copperand/or copper compounds, or combinations thereof.

FIG. 4 provides an illustration of conductive layer 130 formed by anelectroplating process. The present invention is not limited to anyparticular electroplating process, but only to use of the seed filmdescribed herein in any plating process.

The conductive layer 130 formed using the seed film 40 of the presentinvention can be used in any number of structures on the substrateassembly 44. For example, the conductive layer 130 formed according tothe present invention can be used in fabricating electrodes, such asthose used in container or trench capacitors, on the substrate assembly44. The conductive layer 130 can also be used in forming otherstructures, such as interconnects, contacts, or vias.

FIG. 5 shows one example of a capacitor structure 208 formed using aseed film according to the present invention. In the present example,the capacitor 208 includes a bottom electrode 210, a dielectric layer212 and a top electrode 214. Generally, the capacitor 208 includes atleast one electrode (either the bottom electrode 210, the top electrode214, or both) that is formed using at least a seed film (not shown). Oneskilled in the art will recognize that the electrodes may be formedusing more than one conductive layer and/or multiple materials. Examplesof materials used in forming the conductive layers include thosediscussed in the present application (e.g., platinum, ruthenium,rhodium, etc.). Additional conductive layers can also be deposited informing the electrodes of the present invention. The additionalstructures necessary for the operation of the capacitor 208 are notshown.

Generally, the seed film of the present invention can be used to formany one, or both, the bottom electrode 210 and/or the top electrode 214of the capacitor 208. When the seed film is used in forming the bottomelectrode 210, the seed film can be formed over the surface 226 thatforms an opening 230 in the substrate assembly 204. A conductive film,as previously discussed, can be deposited on the substrate assembly 204for use in the electroplating process. The bottom electrode 210 can thenbe electroplated as described herein (like that of 70) over the seedfilm in the opening 230. In addition, the seed film can optionally beformed over the dielectric layer 212 and used in plating a conductivelayer of the top electrode 214.

The electrodes 210 and 214 of the present invention can be formed from avariety of conductive materials that can undergo the electroplatingprocess, and may also include layers deposited using other processes(e.g., CVD). For example, a noble metal can be electroplated over theseed film in forming one or both of the electrodes 210 and 214.Preferably, the electroplated portion of the electrode is formed ofplatinum or a platinum alloy. Other electrodes could be formed byelectroplating using any number of metals and/or metal alloys,including, but not limited to, copper, nickel, ruthenium, rhodium, andalloys thereof.

The present invention is further illustrated by the following examples,but the particular materials and amounts thereof recited in theseexamples, as well as other conditions and details, should not beconstrued to unduly limit this invention.

EXAMPLES Example 1 Process for ALD Formed Pt—RhO_(x) Seed Film

ALD was carried out using an experimental test reactor (custommanufacture) operating under high vacuum. All seed films were depositedon BPSG surfaces. Seed films were deposited on the BPSG surfaces at awafer surface temperature of about 100 degrees to about 112 degreesCelsius.

The Pt—RhOx seed film of the present example includes multiple series oflayers of rhodium and multiple series of layers of platinum, both ofwhich are deposited by ALD. Generally, in a rhodium forming cycle, theBPSG surface was exposed to a 5 second dose of CpRh(CO)₂ so as to coverthe BPSG surface. The ALD chamber was then purged with 50 SCCM of heliumfor 5 seconds. The rhodium precursor was then exposed to 50 SCCM ofoxygen (O₂) for 5 seconds. The resulting rhodium layer had less than amonolayer of coverage. A vacuum was then applied to the ALD chamber for5 seconds. This complete rhodium formation cycle was repeated for atotal of ten (10) times to form the series of rhodium layers.

In a platinum formation portion of the process, the series of platinumlayers were then applied over the ALD formed rhodium. Generally, in aplatinum formation cycle, the BPSG surface having rhodium formed thereonwas exposed to a 5 second dose of MeCpPt(Me)₃ at room temperature from abubbler. The ALD chamber was then purged with 50 SCCM of helium for 5seconds. The platinum precursor and rhodium formed on the BPSG surfacewere then exposed to 100 SCCM of ozone (O₃) for 5 seconds. The ozone isused to convert the platinum precursor to produce a layer of platinum ofless than a monolayer, along with oxidizing the rhodium to produceRhO_(X). A vacuum was then applied to the ALD chamber for 5 seconds.This complete platinum formation cycle was repeated for a total of ten(10) times to form the series of platinum layers.

The protocol of depositing the rhodium layer series and the platinumlayer series was repeated five times, so as to have a total of 100cycles for both the rhodium precursor and the platinum precursor. Theresulting seed film includes a sandwich like structure of platinum andrhodium oxide, e.g., similar to a metal laminate, having a thicknessfrom about 50 to about 150 Angstroms.

Platinum was then plated onto the resulting Pt—RhOx seed film.Electroplating was carried out using a direct current supply operatingat approximately 0.01 A to approximately 0.08 A. A platinum platingmixture included H₂Pt(OH)₆ at a concentration sufficient to provide 12grams of platinum per one liter of platinum plating solution. The pH ofthe platinum plating mixture was adjusted to approximately 11 with KOH.

The resulting electroplated Pt layer and Pt—RhO_(x) seed film was thensubject to a standard peel test. Scratches in a crosshatch pattern werefirst made in the electroplated Pt layer and Pt—RhO_(x) seed film, wherethe scratches extended through both the electroplated Pt layer and thePt—RhO_(x) seed film. SCOTCH tape was then applied to the electroplatedPt layer and removed. Neither the electroplated Pt layer, nor thePt—RhO_(x) seed film, were removed from the BPSG substrate by the SCOTCHtape.

In addition to the standard peel test, the Pt—RhO_(x) seed film wassubject to a photoresist develop test. The Pt—RhO_(x) seed film wasimmersed in positive photoresist developer at room temperature for 30minutes. The Pt—RhO_(x) seed film was then rinsed and examined. Visualinspection indicated that the Pt—RhO_(x) seed film was not removed byexposure to the positive photoresist developer or as a result of thestandard peel test.

Example 2 Process for ALD Formed Platinum Doped Silicon Oxide(Pt—SiO_(x)) Seed Film

ALD was carried out using the experimental test reactor (custommanufacture) operating under high vacuum. All seed films were depositedon BPSG surfaces. Seed films were deposited on the BPSG surfaces at awafer surface temperature of about 235 degrees Celsius.

The Pt—SiO_(x) seed film of the present invention includes multiplelayers of platinum followed by one layer of SiO_(x), where this serieswas repeated at least once. All layers were deposited by ALD. Generally,in a platinum forming cycle, the BPSG surface was exposed to a 5 seconddose of MeCpPt(Me)₃ at room temperature from a bubbler to cover the BPSGsurface. The ALD chamber was then purged with 50 SCCM of helium for 5seconds. The platinum precursor on the BPSG surface was then exposed to50 SCCM of oxygen (O₂) for 5 seconds. The oxygen is used to convert theplatinum precursor to produce a layer of platinum of less than amonolayer. The ALD chamber was then purged again with 50 SCCM of heliumfor 5 seconds. This complete platinum formation cycle was repeatedbetween twenty (20) and fifty-five (55) times.

In the SiO_(x) formation portion of the process, a SiO_(x) layer wasthen applied over the ALD formed platinum. Generally, in the SiO_(x)formation cycle, the BPSG surface having platinum formed thereon wasexposed to a dose of disilane (Si₂H₆) delivered to the ALD reactionchamber at 2.5 SCCM. The ALD chamber was then purged with 20 SCCM ofhelium for 5 seconds. The disilane and platinum formed on the BPSGsurface were then exposed to 50 SCCM of oxygen (O₂) for 5 seconds. Theoxygen is used to convert the disilane to produce the Pt—SiO_(x) seedfilm. The ALD chamber was then purged again with 50 SCCM of helium for 5seconds. The resulting platinum doped silicon oxide (e.g., Pt—SiO_(x))seed film had a thickness from about 50 to about 150 Angstroms.

Platinum was then plated onto the resulting Pt—SiO_(x) seed film.Electroplating was carried out using a direct current supply operatingat approximately 0.01 A to approximately 0.08 A. A platinum platingmixture included H₂Pt(OH)₆ at a concentration sufficient to provide 12grams of platinum per one liter of platinum plating solution. The pH ofthe platinum plating mixture was adjusted to approximately 11 with KOH.

The resulting electroplated Pt layer and Pt—SiO_(x) seed film was thensubject to a standard peel test. Scratches in a crosshatch pattern werefirst made in the electroplated Pt layer and Pt—SiO_(x) seed film, wherethe scratches extended through both the electroplated Pt layer and thePt—SiO_(x) seed film. SCOTCH tape was then applied to the electroplatedPt layer and removed. Neither the electroplated Pt layer, nor thePt—SiO_(x) seed film, were removed from the BPSG substrate by the SCOTCHtape for thickness of less than about 500 angstroms of the Pt—SiO_(x)seed film.

In addition to the standard peel test, the Pt—SiO_(x) seed film wassubject to a photoresist develop test. The Pt—SiO_(x) seed film wasimmersed in positive photoresist developer at room temperature for 30minutes. The Pt—SiO_(x) seed film was then rinsed and examined. Visualinspection indicated that the Pt—SiO_(x) seed film was not removed byexposure to the positive photoresist developer or as a result of thestandard peel test.

Example 3 Process for ALD Formed Pt Seed Film

ALD carried out using the experimental test reactor (custom manufacture)operating under high vacuum. The platinum seed film was deposited onBPSG surfaces. The seed film was deposited on the BPSG surfaces at awafer surface temperature of about 235 degrees Celsius.

The platinum seed film of the present invention was deposited by ALD.Generally, in the platinum forming cycle, the BPSG surface was exposedto a 5 second dose of MeCpPt(Me)₃ at room temperature from bubbler tocover the BPSG surface. The ALD chamber was then purged with 50 SCCM ofhelium for 5 seconds. The platinum precursor on the BPSG surface wasthen exposed to 50 SCCM of oxygen (O₂) for 5 seconds. The oxygen is usedto convert the platinum precursor to produce a layer of platinum of lessthan a monolayer. The ALD chamber was then purged again with 50 SCCM ofhelium for 5 seconds. This complete platinum formation cycle wasrepeated between 50 and 200 times. The resulting platinum seed film hada thickness from about 50 to about 150 Angstroms.

Platinum was then plated onto the resulting Pt seed film. Electroplatingwas carried out using a direct current supply operating at approximately0.01 A to approximately 0.08 A. A platinum plating mixture includedH₂Pt(OH)₆ at a concentration sufficient to provide 12 grams of platinumper one liter of platinum plating solution. The pH of the platinumplating mixture was adjusted to approximately 11 with KOH.

The resulting electroplated Pt layer and Pt seed film were then subjectto a standard peel test. Scratches in a crosshatch pattern were firstmade in the electroplated Pt layer and Pt seed film, where the scratchesextended through both the electroplated Pt layer and the Pt seed film.SCOTCH tape was then applied to the electroplated Pt layer and removed.100 percent of the platinum seed film failed the peel test, as theelectroplated Pt layer was removed with the tape.

Example 4 Process for ALD Formed Pt—Rh Seed Film

ALD was carried out using the experimental test reactor (custommanufacture) operating under high vacuum. All seed films were depositedon BPSG surfaces. Seed films were deposited on the BPSG surfaces at awafer surface temperature of about 100 degrees to about 115 degreesCelsius.

The Pt—Rh seed film of the present example includes multiple series oflayers of rhodium and multiple series of layers of platinum, both ofwhich are deposited by ALD. Generally, in the rhodium formation cycle,the BPSG surface was exposed to a 5 second dose of CpRh(CO)₂ so as tocover the BPSG surface. The ALD chamber was then purged with 50 SCCM ofHe for 5 seconds. The rhodium precursor was then exposed to 50 SCCM ofoxygen (O₂) for 5 seconds. The resulting rhodium layer had less than amonolayer of coverage. A vacuum was then applied to the ALD chamber for5 seconds. This complete rhodium formation cycle was repeated for atotal of 5 times to form the series of rhodium layers.

In the platinum formation portion of the process, the series of platinumlayers were then applied over the ALD formed rhodium. Generally, in aplatinum formation cycle, the BPSG surface having rhodium formed thereonwas exposed to a 5 second dose of MeCpPt(Me)₃ at room temperature from abubbler. The ALD chamber was then purged with 50 SCCM of helium for 5seconds. The platinum precursor and rhodium formed on the BPSG surfacewere then exposed to 50 SCCM of ozone (O₃) for 5 seconds. The resultingplatinum layer had less than a monolayer of coverage. A vacuum was thenapplied to the ALD chamber for 5 seconds. This complete platinumformation cycle was repeated for a total of 30 times to form the seriesof platinum layers.

The protocol of depositing the rhodium layer series and the platinumlayer series was repeated 9 times, so as to have a total of 180 cyclesfor both the rhodium precursor and the platinum precursor. The resultingseed film includes a sandwich like structure of platinum and rhodium,e.g., similar to a metal laminate, having a thickness from about 50 toabout 150 Angstroms.

Platinum was then plated onto the resulting Pt—Rh seed film.Electroplating was carried out using a direct current supply operatingat approximately 0.01 A to approximately 0.08 A. A platinum platingmixture included H₂Pt(OH)₆ at a concentration sufficient to provide 12grams of platinum per one liter of platinum plating solution. The pH ofthe platinum plating mixture was adjusted to approximately 11 with KOH.

The resulting electroplated Pt layer and Pt—Rh seed film was thensubject to a standard peel test. Scratches in a crosshatch pattern werefirst made in the electroplated Pt layer and Pt—Rh seed film, where thescratches extended through both the electroplated Pt layer and the Pt—Rhseed film. SCOTCH tape was then applied to the electroplated Pt layerand removed. 100 percent of the Pt—Rh seed films tested were removedfrom the BPSG substrate by the SCOTCH tape.

A number of implementations and embodiments of the invention have beendescribed. For instance, seed films for use in electroplating of metallayers in integrated circuit substrate assemblies have been described.The seed films are conformal to the structures of the substrateassemblies and allow for the electroplating of metal layers onto thesubstrate assemblies. The seed films may be utilized in a variety ofsubstrate assembly structures such as where conductive layers that areboth thin and conformal are desired. It is understood that variousmodifications can be made without departing from the scope of theinvention. Accordingly, these and other embodiments are within the scopeof the following claims.

1-74. (canceled)
 75. A seed film for use in electroplating a conductivelayer, comprising: one or more noble metal layers, wherein each layer ofthe one or more noble metal layers is no greater than a monolayer; andone or more silicon oxide layers, wherein each layer of the one or moresilicon oxide layers is no greater than a monolayer.
 76. The seed filmof claim 75, wherein the seed film further comprises alternating layersof the one or more noble metal layers and the one or more silicon oxidelayers.
 77. The seed film of claim 75, wherein the one or more noblemetal layers are selected from a group consisting of iridium, ruthenium,platinum, and rhodium.
 78. The seed film of claim 75, wherein the one ormore silicon oxide layers comprises silicon dioxide.
 79. The seed filmof claim 75, wherein the first series of noble metal layers areplatinum, and the second series of silicon oxide layers are silicondioxide.
 80. The seed film of claim 75, wherein the seed film has athickness of no less than 20 angstroms and no greater than 500angstroms. 81-101. (canceled)
 102. A seed film for use in electroplatinga conductive layer, comprising: one or more platinum layers, whereineach layer of the one or more platinum layers is no greater than amonolayer; and one or more silicon dioxide layers, wherein each layer ofthe one or more silicon dioxide layers is no greater than a monolayer.103. The seed film of claim 102, wherein the seed film further comprisesalternating layers of the one or more platinum layers and the one ormore silicon dioxide layers.
 104. The seed film of claim 103, whereinthe seed film has a thickness of no less than 20 angstroms and nogreater than 500 angstroms.
 105. The seed film of claim 75, wherein theone or more noble metal layers comprises iridium.
 106. The seed film ofclaim 75, wherein the one or more noble metal layers comprisesruthenium.
 107. The seed film of claim 75, wherein the one or more noblemetal layers comprises platinum.
 108. The seed film of claim 75, whereinthe one or more noble metal layers comprises rhodium.
 109. The seed filmof claim 75, wherein the one or more noble metal layers individuallycomprise an alloy of different noble metals.
 110. The seed film of claim75, wherein the seed film is at least 100 angstroms thick.
 111. The seedfilm of claim 107, wherein the seed film is no greater than 300angstroms thick.